diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index 9820d71..f3bc8aa 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -154,7 +154,9 @@ class PostsController < ApplicationController
   #
   # @return [Hash]
   def filter_params
-    @filter_params ||= params.permit(:q, :category, :layout, :page).to_hash.select { |_, v| v.present? }
+    @filter_params ||= params.permit(:q, :category, :layout, :page).to_hash.select do |_, v|
+      v.present?
+    end.transform_keys(&:to_sym)
   end
 
   def site